Do Top Bucks Dominate Deer Breeding?

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dominant buck
In some cases, a deer herd’s most impressive buck seldom, if ever, reproduces until the area’s dominant buck gets killed. And in other cases, average bucks were much more successful producing fawns than were big bucks.

One of the herd’s most impressive bucks apparently never reproduced. “He carried a very high-scoring rack, but we found no evidence he ever sired a fawn,” DeYoung said.

Another big buck, however, enjoyed at least three years of reproductive success. DeYoung said this buck, No. 166, had a gross Boone and Crockett score of 160 when it was found dead. It sired nine fawns in three years.

Several bucks not only sired more than one fawn in their life, they sired multiple fawns in one year. How productive were they? One buck sired 11 fawns in five years, including six in one year; two bucks sired five fawns in two years, with one siring four in one year; one buck sired seven fawns in two years, including six in one year; two bucks sired six fawns in four years, with one of them siring four in one year; and one buck sired seven in four years, including four in one year.

Intimidation Factors

Geist has long believed some older bucks “opt out” of breeding, maybe because earlier attempts led to severe thrashings from more aggressive bucks. When Geist was studying unhunted mule deer herds, he discovered some trophy buckswould not challenge other bucks for breeding rights. Some of these big bucks hid from other bucks, retreating into heavy cover when encountering potential foes. They didn’t leave the area, however, leading Geist to think their strategy was to be nearby in case a breeding opportunity fell into their laps.

This strategy also paid off occasionally over longer time periods. Geist watched one muley buck avoid breeding for three years before his patience was rewarded. It survived a downturn in the population cycle, and then emerged as the herd’s dominant breeder when his competition was no longer around.

“He then bred everything in sight,” Geist said.

These timid bucks benefit physically, however. Because they expend so little energy during the rut, and do not have to spend all winter recuperating from wounds and weight loss caused by intense rutting activity, their bodies are primed to produce outsized antlers the next year. If this pattern repeats itself two or three years in a row, bucks can produce awesome racks by their second and third years of breeding inactivity.

If that scenario is accurate, the alternative also holds true. Geist notes that nature can exact a heavy price on aggressive trophy bucks. The herd’s most aggressive breeders incur many injuries and go into winter malnourished after weeks of chasing, fighting and breeding with little food or rest. If they survive winter, their body spends so much energy recuperating, that little is left for growing antlers. However, their confident, hot-headed temperament remains, and they continue to fight for breeding rights in autumn.

Professor Stephen Demarais of Mississippi State University said such scenarios make sense, but data from the study in Oklahoma can’t support such observations. “That very well might explain some things, but it’s nothing we can verify with our research,” he said.

Intimidation Stress

John J. Ozoga, who spent 30 years studying whitetails in the 1-square-mile Cusino enclosure in Michigan’s Upper Peninsula, recalls a buck similar to the shy muley Geist described. Ozoga said he seldom saw this whitetail buck, and noticed it never associated with other bucks. He doubts it competed with other bucks for breeding rights. The buck had an impressive rack, but when it was trapped and placed with other deer in a holding pen for census work, its low dominance ranking was obvious to researchers.

When Ozoga’s research team checked the buck’s blood, they discovered physical evidence of its timid nature. Ozoga said the buck had high “plasma progesterone values.” Progesterone is usually regarded as a female hormone, but it is produced in quantity when animals are stressed. When the herd’s most dominant breeder buck was later poached, however, the timid buck immediately became the herd’s dominant buck. When its blood was next checked, its progesterone level was normal. The buck remained the dominant breeder until it was removed from the enclosure three years later.

Top Bucks Conclusion

By now it should be clear that a buck’s breeding success is highly variable and unpredictable. Even so, many deer hunters and landowners develop and implement deer management plans with the assumption that big bucks do most of the breeding. In reality, the whitetail’s breeding tendencies remain unclear. Further, even with insights coming from Mississippi State University, DeYoung said another goal remains in the works.

“We would like to see which does, in terms of age and size, are being bred,” he said.

How would DeYoung answer the question often asked by landowners and lease-holders: “Should I protect bucks that have the most desirable antlers?”

“You won’t guarantee success, but if it makes you feel better, the longer a buck is out there, the more he might get the chance to sire at least a few fawns,” DeYoung said.



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